The subject invention relates to a method for predicting and communicating the transient hygrothermal behavior and performance of installed building components. The method includes inputting unique inputs into a commercially available transient hygrothermal simulation software program to create a highly unique and useful software model for predicting, as a function of time, the transient hygrothermal behavior (e.g. the moisture content) of an installed building component (e.g. an installed building material or installed building material assembly) in a building where the interior environment of the building is materially affected by the exterior environment such as but not limited to an unfinished building without a working heating, ventilating, and air conditioning system (HVAC system). The method of the subject invention further relates to the technique of utilizing of the created transient hygrothermal behavior software model with regard to one or more defined performance characteristics of an installed building component as a guide to evaluate the performance of an installed building component so that the performance of the building component and/or other building component(s) in contact with or adjacent the building component will not be adversely affected by the hygrothermal behavior of the building component. While the method of the subject invention can be used for numerous applications, one specific application for which the method of the subject invention is particularly well suited is the determination of when the transient moisture content of a moisture containing building component (e.g. a damp spray-in insulation) installed in a wall, ceiling, floor, or roof of an unfinished building permits the enclosure and sealing of the installed building component within the wall, ceiling, floor, or roof without adverse consequences related to the moisture content of the installed building component.
As discussed on the web page of the Building Technology Center of the Oak Ridge National Laboratory entitled “Software/WUFI-ORNL/IBP/Introduction”, in addition to the thermal properties of a building component and the impact of those thermal properties on heating losses, the hygric behavior of building components should also be considered in connection with building construction.
For example, permanently increased moisture content in an installed building component, such as but not limited to building insulation, may result in moisture damage to or reduced performance of the building component and/or other building components in contact with or adjacent the building component, such as but not limited to dry wall boards, wooden framing members, etc. and may also result in elevated surface moisture levels in living rooms that can lead to hygienic problems and health risks due to mold growth. With regard to building component performance, the thermal and hygric behavior of a building component are closely interrelated in that increased moisture content favors heat losses and thermal conditions affect moisture transport. Through hygrothermics, the thermal properties and hygric behavior of building components and the mutual interdependence of the thermal properties and hygric behavior of building components can be determined and appropriate measures taken to assure that installed building components do not permanently retain a moisture content that can materially and adversely affect the performance of the building component, degrade the building component or adjacent building components, or cause hygienic problems.
One simulation tool for predicting the transient hygrothermal (heat and water) behavior of installed building components is the commercially available WUFI hygrothermal software package (Fraunhofer Institut Bauphysik). This software package outputs temperature, water content, and relative humidity in various components of a building assembly defined by the user of the software package. In a typical simulation using this software package, the building assembly is exposed to a simulated climate on its exterior facing side based on collected climate data for many regions around the world and a simulated interior environment assumed to be controlled and held at a near-constant temperature and humidity normal for a HVAC system. While the above exterior climate and interior environment inputs may be acceptable for simulating certain applications with this type of software, there has remained a need for predicting the transient hygrothermal behavior of installed building components in building construction applications where the interior environment is not controlled and maintained at a near-constant temperature and humidity such at that normally maintained by a HVAC system. An example of such an application occurs in residential building construction wherein while the building is under construction, many building components of the building envelope may be assembled before the HVAC system is operational. In such a situation, the local climate can impact both the exterior and the interior sides of installed building component(s) whereby transient hygrothermal simulations based on a simulated interior environment that is assumed to be controlled and held at a near-constant temperature and humidity normal for a HVAC system would inaccurately predict the transient hygrothermal behavior of the installed building component(s). Such inaccuracies in the transient hygrothermal behavior of the installed building component(s) could produce adverse consequences. In the method of the subject invention, simulations for predicting the transient hygrothermal behavior of installed building components in buildings where the interior environment is not maintained at a near-constant temperature and humidity normal for a HVAC system (e.g. residential and other buildings under construction or renovation where the HVAC is not operational) are produced that accurately predict the transient hygrothermal behavior of installed building components in such an application for specific building design and climate locations as well as a broad range of building designs and climate conditions.